Does glutathione pose a danger or have side effects? Glutathione facts: 1. Glutathione is an important antioxidant in the body that helps protect cells from damage caused by free radicals. It is found in almost every cell and is composed of The Food and Drug Administration (FDA) warns the public on the dangers associated with the use of injectable lightening agents such as glutathione and Vitamin C. In the Philippines, several health and Excessive glutathione intake contributes to chemotherapy resistance in breast cancer: a propensity score matching analysis World Journal of Surgical Oncology Springer Nature Link